The present invention relates to concrete products to be used under the environmental conditions wherein microorganisms and plants can grow. More particularly, the invention relates to concrete products for promotion of afforestation for providing the surface of the concrete product body with a green planting.
Recently, the natural environment, especially the esthetics of natural and urban areas has come to be regarded as being important. Above all, because levees, retaining walls of river or seashore banks, protective walls of railway lines, side walls of roads, etc. are constructed of concrete and are unnatural in appearance, it has been proposed that such structures be of green color which is more natural.
Accordingly, there have been developed and produced concrete blocks having plant growth thereon and green-compatible concrete, etc. The concrete having plant growth has a porous structure in which the plant base materials comprising inorganic special soil dispersed with plant seeds are filled, so that the concrete surface can be covered with plant growth in several months.
The green-compatible concrete is designed to be applied to structures, with the aim of covering the roof and wall surface of buildings. It is designed to permit placement of covered soil on the surface of porous concrete and sowing of plant seeds therein.
Furthermore, water quality purifying concrete which attempts to purify water by propagating aquatic plants has been proposed. The objective of this concrete is to allow aquatic plants to grow in the pores thereof.
In the plant-grown concrete block as described above, because the seeds of plants are dispersed in advance in the space of porous concrete block, greengrowing can be attained in a short period of several months. However, the pore space in the surface of the porous concrete block in which the special soil is filled is only in the surface area of the block, and accordingly, the amount of growth is limited. Furthermore, unless the seeds are properly dispersed, plant growth can never be attained. In the case of the green-planted concrete, unless seeds are sown in the covering soil planed on the surface of the porous concrete, no growth can be attained. Furthermore, in the water purifying concrete, unless seeds of aquatic plant are planted in the pore space, a very long period of time is required before aquatic plants naturally grow. As noted above, in known green growing concrete products, unless seeds of plants are filled or planted in the concrete product, greening of the concrete medium is difficult.
The present invention has been made in consideration of the limitations of the conventional products, and its object is to provide concrete products for promotion of afforestation with which the naturally settled seeds of plants germinate and grow without it being necessary to fill or plant seeds on the concrete product body into a state in which microorganisms readily settle. In the case of use in water, the concrete product can serve to attain water purification through formation of organism membranes by settlement of microorganisms.
In order to attain the above object, in the concrete products for promotion of afforestation a first aspect of the invention is a concrete product to be used under the environment in which sufficient amount of water necessary for germination of seeds is supplied. Carbon fibers are planted on a predetermined position of the outer surface of the concrete product body.
In a second aspect of the invention, the carbon fibers are constituted by either collecting carbon fiber filaments in a strand form, or compressing filaments into non-woven fabric form, or knitting filaments into knitted goods, or weaving filaments into oven fabrics, or forming carbon into the compound shape, so that the carbon fiber is integrated into the concrete product body by embedding a part of it therein.
In a third aspect of the invention, the carbon fibers are integrated into the concrete product body by either bundling the carbon fiber filaments in a strand form, or forming the filaments at least partly into braided form and embedding a part of it in the concrete product body facing the surface layer is covered with a protective member.
In a fourth aspect of the invention, the protective member is constituted by a synthetic resin or rubber which is high in elasticity and less apt to cause damage to the carbon fiber filaments.
In a fifth aspect of the invention, there is provided a metal or resin cylindrical second protective member of high strength and excellent durability surrounding the protective member on the position facing the surface layer of the carbon fiber formed concrete product body.
Carbon fiber is charged with a positive electric charge, and the microorganisms which exist in the large number in air or water tend to be charged with negative electric charge. Accordingly, these microorganisms tend to settle on the carbon fibers planted on the surface of the concrete product body. By forming the carbon fiber filaments into a strand form, non-woven fabric form, knitted goods form, woven fabric form, or a predetermined compound shape, the surface are of the carbon fibers on which the microorganisms can settle can be large in proportion to the surface area of the concrete product body.
Under the environments wherein water is supplied to the carbon fiber, the microorganisms which settled on the carbon fiber become sludge. Especially, in a dusty environment such as the side wall of road, dust or waste floating in air is to be deposited on the carbon fiber as sludge. The plant seeds which naturally settle on the carbon fiber germinate and grow by utilizing the sludge as a nutrient.
In the case of the concrete products provided under the water level, in addition to the greening by germination and growth of seeds which float in water and settle on the carbon fiber, organism membranes are formed by the microorganisms settled on the carbon fiber, and water is purified by the membranes.
The protective member which coats the strand form or braid form carbon fiber reduces the load which acts on the root part of the carbon fiber molding planted on the concrete product body, and prevents the carbon fiber filament from coming into direct contact with the concrete body.